05.31.2021

Vercel – ignore GitHub branches

I’m writing this blog post as a follow-up to my other post about deploying Frontity to Vercel with GitHub. After I had set up the GitHub deploy, I installed Dependabot in all my projects, so it updates packages automatically.

I had actually never heard of Dependabot, as I am still quite new to GitHub. But I managed to install it quite easily, and it works like a charm. The only thing I did not like about it, is that for each Dependabot PR, a branch was made. And with Vercel, every branch gets a preview build. That becomes a lot of builds.

So I wanted to see if it was a way I could stop this, and after reading on the Vercel GitHub, and documentation, I found a solution. Vercel has a field called “Ignore build step” in the git settings, which you should read more about. But what I did was make a Bash script that runs before every build is started. The script looks like this:

#!/bin/bash

if [[ $VERCEL_GIT_COMMIT_REF =~ "dependabot" ]] ; then
  echo ">> Skipping deploy!"
  exit 0;
else
  echo ">> Proceeding with deploy."
  exit 1;
fi

My goal was to stop preview builds from Dependabot branches, so I made a regex that checks if the variable $VERCEL_GIT_COMMIT_REF contains the word dependabot. The variable is the name of the branch, and every branch that Dependabot makes contains the word Dependabot. I wrote the script in a file called vercel.sh, which I put in the root of my project.

As you can see, before I added the script, every PR triggered a preview build:

But now, after the script, it looks like this:

As you can see, the preview build is canceled. Here is a quick guide on how to do it:

Make a Bash file

You need to create a bash file (.sh) with these commands, and place it in the project, make sure it is uploaded to the GitHub repo.

#!/bin/bash

if [[ $VERCEL_GIT_COMMIT_REF =~ "dependabot" ]] ; then
  echo ">> Skipping deploy!"
  exit 0;
else
  echo ">> Proceeding with deploy."
  exit 1;
fi

You don’t have to use this to only stop dependabot, you can make a new regex if you want it to stop something else.

Define the script in Vercel settings

In the settings of your project in Vercel, you need to run the script. You do this at the bottom of the Git tab.

My script is called vercel.sh, and it is placed at the root of the project. So I just write “bash vercel.sh”. If you want to, you can place the script in the folder in the project, but then you need to enter “bash relative-path/vercel.sh”.

So now, every time a branch is made that matches your regex, this script will stop it from making a preview build.